Art. XXVI.—Description of a new Species of Petrel (Procellaria affinis).

Transactions and Proceedings of the Royal Society of New Zealand, Volume 7, 1874, Page 215

Art. XXVI.—Description of a new Species of Petrel (Procellaria affinis). By Walter L. Buller, D.Sc., F.L.S., etc. [Read before the Canterbury Philosophical Society, 28th October, 1874.] In the Canterbury Museum I find the skin of a Petrel which appears to be new. There is a ticket attached to it with the following memorandum, “Shot—Potts River, 1872,” and this is all the information I possess about the specimen. It bears a general resemblance to Procellaria cookii, but has longer wings and shorter legs, besides certain differences of plumage which may be due to immaturity. The type specimen of P. cookii, which was obtained off the New Zealand coast, is in the British Museum. In this bird the wing measures from the flexure to the tip 9.25 inches, whereas in the present species, although of similar size, the wing measures 10.5, showing a difference of an inch and a quarter. In P. cookii the bare tibia measures half an inch in length; in this species it is scarcely visible. The plumage likewise differs in the following respects. Instead of the whole upper surface of the wings being blackish-brown, the secondaries and their coverts are ashy-grey narrowly margined with white; the feathers of the back and rump and the upper tail-coverts have darker margins; and there is far less white on the inner webs of the secondary quills. The legs and feet, instead of being yellowish brown with paler webs, as in P. cookii, are (so far as I can judge from the dried specimen) dull yellow

with the extremities and the webs perfectly black. The present bird differs further in having the breast and abdomen almost entirely ashy-grey, but this colour is passing off, and therefore seems to indicate a comparatively young bird in a transitional state of plumage. The inner surface of the wings is pure white, but there is a broad band of slaty-black extending from the elbow to the carpal flexure where it spreads, and is then continued along the outer edge. Procellaria affinis. Sp. nov. Diag.—Supra saturatè cinereus; dorsi plumis et supra-caudalibus nigro terminatis; alarum minimis et alâ spuriâ nigricanti-brunneis; primariis extùs nigricanti-brunneis, intùs albis; secundariis pallidè cinereis, albo angustè marginatis, basaliter albis; rectricibus saturatè cinereis, duabus externis intùs albidis; fronte albâ cinerascenti-nigro variâ; regione suboculari conspicuè cinerascenti-nigrâ; facie laterali guttureque albis; pectore imo et abdomine cinereis plumis basaliter albis; corpore reliquo subtùs albâ, pectoris lateribus cinereo lavatis, hypochondriis et subcaudalibus inferioribus cinereo variis et minutè transfasciatis; subalaribus albis, exterioribus conspicuè nigricantibus: rostro nigro: pedibus sordidè flavis, digito externo et membranis interdigitalis nigris. Hab.—New Zealand. Comparative Statement of Measurements. P. cookii. P. affinis. Extreme length 12·5 inches 13 inches Wing from flexure 9.25 " 10·5 " Tail 4 " 4 " Culmen (following curvature) 1.4 " 1.25 " Lower mandible (from the gape) 1.5 " 1.5 " Bare tibia ·5 " — " Tarsus 1.2 " 1.2 " Middle toe and claw 1.5 " 1.75 " In Procellaria leucoptera and P. mollis again we find very similar plumage; but the former (according to Gould) has the wing 2 inches shorter, although the other proportions are the same; while Procellaria mollis, on the other hand, with a decidedly shorter wing than P. affinis, has the tail nearly an inch longer. It has, moreover, a larger tarsus. The four species are closely related to one another, and form together a very natural group or sub-genus.